TEHRAN (Reuters) -- Iran has put several leading reformers in the dock, official media reported, in its fourth mass trial of people accused of fomenting unrest after June's disputed presidential election.

Those tried in a Revolutionary Court on August 25 included former Deputy Interior Minister Mostafa Tajzadeh, former Deputy Foreign Minister Mohsen Aminzadeh, former government spokesman Abdollah Ramezanzadeh, and Iranian-American scholar Kian Tajbakhsh, news agencies said.

Saaed Hajjarian, a former deputy intelligence minister turned architect of Iran's reform movement, was also among the accused, the official IRNA news agency said. Hajjarian was disabled after an assassination attempt in 2000.

"In the fourth court session, the elements and plotters of the recent riots and disturbances in Iran will be put on trial and some of them are expected to present their defiance," IRNA said.

The June 12 election plunged the Islamic republic into its most serious internal crisis since the 1979 Islamic Revolution and exposed deep divisions in its ruling elite.

Analysts regard the trials as an attempt by the authorities to uproot the moderate opposition and put an end to the street protests that erupted after the poll.

Most of the former officials held their positions during the 1997-2005 presidency of Mohammad Khatami, who backed moderate opposition leader Mir Hossein Musavi in the election against the incumbent, hard-liner Mahmud Ahmadinejad.

Musavi and Mehdi Karrubi, who came second and fourth in the election respectively, say the vote was rigged to secure the reelection of Ahmadinejad.

The authorities deny the charge, saying it was the "healthiest" vote the country has had in the past three decades.

Mass Trials Condemned

Iran has held three mass trials already this month of more than 100 detainees, including a former vice president and other senior politicians, on charges including acting against national security, which is punishable by death under Iran's Islamic law.

French teaching assistant Clotilde Reiss and two Iranians working for the British and French embassies in Tehran were among those tried on August 8.

Western countries and human rights groups have condemned the trials. After the first session on August 1, Khatami said it violated Iran's constitution and Musavi said confessions by some of the accused were made under duress.

Rights groups say hundreds of people, including senior pro-reform politicians, journalists, activists, and lawyers, have been detained since the presidential election. Many of them are still in jail.

Iran accuses the West, particularly the United States and Britain, of inciting the unrest, in which at least 26 people were killed. They deny the charge. Hard-liners have called for Musavi and Karrubi to also be arrested.